Every day modern consumers and workers are aided by dozens of electric motors, which convert electric current and voltage into torques and motions. These motors adjust the seats, windows, mirrors, and even steering in cars; bring to life the latest robotic pets; power blenders; drive refrigerator and air-conditioner compressors; wash our clothes and dishes; open our canned goods; drill, saw, and sand wood; and on and on. In factories, electric motors drive CNC milling machines, lathes, robotic arms, conveyer belts, fork-lifts, vacuum systems, hydraulic pumps, and air compressors. Even semi-autonomous robots exploring our solar system use electric motors. The trend is for increased adoption of high performance motors and especially adoption of networks of distributed motors.
The extraordinarily dense scale of integrated circuits and other exponentially improving technologies that support machine intelligence, such as embedded processors, tiny electronic sensors, and even high-density power storage, set expectations that electric actuators, especially their electronic controllers, will follow a similar rapid improvement trend. But, improvements in electric motor controllers, such as power-density (W/cm3), have been painfully slow.
This is especially the case for high-performance motor drives that tend to have sophisticated circuits that require a mix of both noisy power components/circuits and noise-sensitive components and circuit signals. Those trained in the art are taught that bringing a noisy component within close proximity to sensitive component increases Electromagnetic Interference (EMI) for the sensitive component. Consequently, those skilled in the art keep the noisy component and the sensitive component spaced apart from each other to significantly minimize if not avoid this. However, those trained in the art also know that distancing the noisy and sensitive components increases the impedance across a common ground. Once the integrity of that ground is lost to impedance, noise easily corrupts sensitive analog and digital-logic signals.
Faced with this dilemma, those trained in the art apply galvanic isolation (e.g. isolation transformers, active opto-isolators, and the circuits that support them) liberally to separate noisy and sensitive components/circuits and bypass the ground-impedance issue altogether. This solution also has the advantage of allowing unrestricted airflow for ample convection cooling. This solution however, is at the cost of increased size, increased power requirement and increased complexity.
In direct opposition to the increase in size is the demand for smaller overall package size to accommodate higher numbers of motors and controllers in cramped spaces. The explosive demand for controllers with more performance in a smaller package thus, grows unabated. It is difficult, however, to decrease the size substantially without unduly restricting air flow (e.g., air flow for cooling) which can create internal hot spots that ultimately lead to controller failure.
It thus would be desirable to provide a controller for a motor that is ultra compact, which can be mounted proximal to the motor and which is relatively insensitive to EMI affects from power-level circuitry. It would be particularly desirable to provide such a controller that embodies a common unipotential ground for noisy power circuitry that energizes the windings of the motor as well as the signal circuitry that controls this energization in response to signals from one or more sensors. Such a controller also would be desirably smaller in comparison to prior art controllers that handle comparable power. It also would be desirable to provide such a controller having fewer components as compared to such prior art controllers. It also would be desirable to provide apparatuses and the like that embody such controllers as well as methods related thereto. Such controllers preferably would be simple in construction and less costly than prior art controllers.